2007 30,4 stroke efi ; low speed/rpms at full throttle

[Jrcantu]

I bought a used motor. It's a tiller on a 15x48 Jon. Previous owner said they just replaced fuel pump. Starts fine idles good, shifts good. Problem is at full throttle only gets about 3000 rpms/ 8 mph (estimated; don't have a tachometer). Someone suggested perhaps Nuetral safety switch not opening when shifting into gear thus limiting rpms but tested it with ohm meter and it does open & close. Anyone have any ideas or suggestions? Thank you for any help. Oh yea, went to a prop shot and purchased new SS prop also, but same result.

 

[Gavin27]

Could be many things. Need to start process of elimination. Start with spark. Check your plugs, timing, coils, stator, regulator. Looks for old wires or some that have poor connections from build up. clean those. If all of those are good then move onto fuel. Check all lines for holes, leaks, primer ball, replace fuel filter etc. My "guess" would be something to do with high speed windings, or fuel filter.

Does it go over 3000rpm in Neutral in your driveway? Or was it only in the water? Does it bog down when you try to go past 3k rpm or just sits at 3k purring normally?

 

[Jrcantu]

I don’t have a tachometer on it as it’s a tiller but it doesn’t bog down at all, runs great at maxed out rpms & speed ( estimated 3000/ 8- 10 mph). Has a new SS prop.